Sodium and chloride distribution in grapevines as a function of rootstock and irrigation water salinity

The salt tolerance of rootstocks is often assessed based on their ability to limit uptake of sodium (Na) and chloride (Cl) ions. Here, we evaluated the effects of three irrigation salinity levels (electrical conductivity of 1.2, 2.7, and 4.2 dS/m) on Cabernet Sauvignon grapes grafted on Ruggeri, Paulsen, 216/3, and 101/14 rootstocks. Growth parameters were affected by salinity level but not by rootstock, and yield was not affected by either variable. Ruggeri and 216/3 were most effective at limiting uptake and accumulation of Na and Cl in scion petioles, wood, and must. The rootstocks differentially excluded Na and Cl from vines; 216/3 and Ruggeri showed the best performance for Na and Cl, respectively. More Na than Cl accumulated in woody tissue. Mortality rates as high as 17.5% were found for poor salt-excluding rootstocks irrigated with the highest salinity water. The apparent breakdown of tolerance mechanisms, leading to salt damage and vine mortality, might be due to Na reaching critical levels in woody tissues. The ability to exclude Na and Cl from shoots and fruit was found to (a) increase wine quality by reducing concentrations of salt ions in must and wine, and (b) reduce mortality rates that result from long-term exposure to salt.